2-amino-4-nitrophenoxyethanol and process of producing the same



Patented May 15, 1928.

UNITED STATES PATENT OFFICE.

OSCAR KNECHT, 'OF BINNINGEN,

CAL WORKS FORMEBLY NEAR BASED, SWITZERLAND, ASSIGNOR TO CHEMI- SANDOZ,OF BASED, SWITZERLAND, A. FIRM.

No Drawing. Application filed December 18,

2.4-dinitrophenoxyethanol is contrarily to the 2.4dinitrophenolalkylethers, easily hydrolized by alkaline agents, as forinstance by. dilute caustic soda. This splitting ofi i of the' glycolradical, which happens very easily, is the reason why the preparation ofthis compound, after known prescriptions, could hitherto only beperformed in an imperfect manner. It was, therefore, not to be foreseenit would be possible to transform the 2.4-dinitrophenoxyethanol into thehitherto unknown nitroaminocompound by means of alkaline reducing"agents.

It has ,now been found that this is possible 5 and almost withoutsaponification, if for instance 2.4-dini-trophenox ethanol is treatedwith alkali sulphides or a ali polysulphides at warm temperature. By aneasy. reaction and without by-products, 2-amino-4-nitrophenoxyethanol isformed, which is more diflicultly saponifiable than the dinitrocompound.This derivative of m-nitraniline, which so far has never been prepared,may

be used as intermediate product for the.

5 preparation of valuable dyestuffs. The following example illustratesthe process of making such product:

To an aqueous suspension. of177 kg. of 2.4-dinitrophenoxyethanolanaqueous soluj 'tion of sodium tetrasulph-ide,-prepared from 240 kg. ofsodiuxnsulphide and 96 kg. of sulphur, is added, under vigorous stirrinat about 60- (1., whereby an immediatereduc tion 'ta'kes 5 mixture isept a short time-at a tempera; ture of 60 0., then cooled down to C;After neutralization with -kg.v of hydrochloric acid thenitroaminocompoundj is pre cipitated as an orange colored deposit con- 1taining sulphur. The nitroaminocompound is then dissolved 80 kg. ofhydrochloricacid, the sulphur remaimng undissolved. The hydrochloridesolution-canbe used as such, or the base 6 can be precipitated withsoda. In the latter ,ried to a large extent.

lace under self heating. The" p of2.4-dinitrophenoxyethanol with analkali 80 in 500 litresof water and 1926, Serial No. 154,652, and inGermany December 19, 1925.

case the base separates as a brown oil, which solidlfies by stirrin to agolden-yellow crys-, talline deposit. The hitherto unknown 2-.amino-4-nitrophenoxyethanol melts at 111 112 C. and is easily solublein alcohol and very difiicultly soluble in benzene.

The hitherto unknown 2.4-dinitrophenoxyethanol is easily formed'byheating 2.4-dinitro-l-chlorobenzene with glycol and soda for some hoursat a temperature of 90100 C. The reaction product is then recrystallizedfrom water,v whereby yellowish crystal needles are obtained, melting at111-112 C. The working conditions are not limited to those of the aboveexample, but may be Va- For instance, the dinitrocompound may be addedto the reducing agent or the reaction may be performed in an aqueousalcoholic or a pure alcoholic solution. Further the reduction can alsotake place. at other temperatures and with other polysulphides andotherquantities of these agents:

What I claim is: a 1 1. A process for the preparation of 2- 7OaminoA-nitrophenoxyethanol, consisting in treating2.4-dinitrophenoxyethanol with an alkali sulphide as reducing agent.

2.-A' rocess for the preparation of 2- aminoi-nitrophenoxyethanolconsisting in treating 2.4-din1trophenoxyethanol with an alkalipolysulphi'de as reducing agent.

3. The herein described 2-amino-4-nitrohenoxyethanol obtained by thetreatment sulphide and constituting an intermediate product fordye'stufis inform of yellow crystals easily soluble-in alcohol and veryd 1f- 'ficultly soluble in benzene, dissolving easily in dilute mineralacids to quantitatively di', 35

azotizable solutions.

In witness whereof I have hereunto slgned my name this 26th day ofNovember 1926.

osoAR KNECHT.

